1. Field of the Invention
The present invention relates to a rotary press for printing on paper web and for processing printed paper web, and particularly to a rotary press wherein printed paper web is heated and then cooled so as to stabilize the ink of an image printed on the paper web, and subsequently the printed paper web is processed.
2. Description of the Related Art
A rotary press for printing on paper web generally performs post-printing processes, such as folding and cutting, as well as printing. For example, as shown in FIG. 4, a schematic version of FIG. 2-1 on page 11 of "Rotary Offset Printing" (Nippon Insatsu Shinbun-sha, First Edition, Oct. 20, 1990), such a rotary press comprises a paper web supply section, a paper web feed section (the paper web supply section and the paper web feed section constitute a paper web supply apparatus), a printing section (printing apparatus), a drying section (drying apparatus), a cooling section (cooling apparatus), a first folder, and a second folder (the first and second folders constitute a post-printing processing apparatus).
The drying apparatus in such a conventional rotary press is intended to "evaporate a solvent for ink within the drying apparatus by heating," as described in the aforementioned "Rotary Offset Printing," page 35, left column, "4. Drying apparatuses and Cooling Roller Units," lines 11-12. Further, as described in the same literature, the same page, right column, lines 5-6, "at present, most drying apparatuses are of the full hot-air type, in which hot air discharged from nozzles blows against paper web."
Such a drying apparatus has a relatively long linear path of paper web so as to blow hot air against both sides of paper web running through the path, as described in the above-cited "Rotary Offset Printing," from page 36, left column, line 4, to page 39, left column, line 2, or in Japanese Utility Model Application Laid-Open (kokai) No. 1-156933. Thus, the structure of the drying apparatus is complex and large scaled. As shown in FIG. 4, such a drying apparatus is very large as compared with a printing apparatus.
Also, a conventional drying apparatus disclosed in Japanese Utility Model Application Laid-Open (kokai) No. 63-106635 comprises heating rollers and nozzles. The heating rollers are disposed so as to contact running paper web on both sides thereof. The nozzles are arranged so as to blow hot air against the running paper web from both sides thereof in the vicinity of and on the upstream and downstream sides of the heating rollers. Thus, the paper web is heated by the heating rollers as well as by hot air.
This drying apparatus may replace the aforementioned full hot-air type drying apparatus.
The drying apparatus disclosed in Japanese Utility Model Application Laid-Open (kokai) No. 63-106635 is intended to improve heating efficiency, which is rather poor when heating is performed only by hot air. As described in the specification, since the contact between the heating rollers and the paper web is instantaneous, the heating effect of the heating rollers is very small. Thus, combined use of the heating rollers and hot air is unavoidable. Accordingly, like a full hot-air type drying apparatus, this drying apparatus has a structure which is complex and large scaled as compared to that of the printing apparatus.
Since the above-mentioned conventional drying apparatuses which utilize hot air are large scaled, a rotary press equipped with such a drying apparatus requires a wide space for installation thereof.
Because of the complex and large-scaled structure, the above-described conventional drying apparatuses have a high cost of manufacture. Accordingly, the installation of a rotary press equipped with such a drying apparatus requires great expense.
Further, since the above-mentioned conventional drying apparatuses require a large amount of hot air to be circulated over a relatively long path of running paper web, a large amount of energy is consumed, resulting in a high running cost for a rotary press equipped with such a drying apparatus.